Three governments issue ADs after crash
First case in nineteen years of GA8 structural failure
What does a CAA need to know in order to ground a plane
In order to issue an emergency airworthiness directive, what must a Civil Aviation Authority know? The recent Max 8 tragedy involved the grounding of the aircraft by a number of CAAs information that was both preliminary and inconclusive.
A more recent accident in which emergency ADs (EASA, Australia and New Zealand) were issued after another tragedy. Using that fact situation, an examination of what proof is required in order to exercise the most severe airworthiness action available to a CAA?
What is known about the Skydiving GA 8 crash?
In 2000 the Australian Civil Aviation Safety Authority certificated the GippsAero GA8 Airvan to FAR 23 Amendment 48. That aircraft is now technically the Mahindra Airvan 8 in that the Indian company acquired the Australian aircraft manufacturer in 2008. Since then, approximately 240 GA8’s have been manufactured and are in service around the world for passenger services; freight; sightseeing; parachuting; observation and search and rescue (US Civil Air Patrol)
Since then, according to Bureau of Aircrafts Accidents Archives (the above chart found at this link), the Airvan was involved in five accidents (pilot error, weather (2), maintenance issues (powerplant) and the recent crash in Sweden).B3A described the factors which it identified:
It climbed to an altitude of 13,000 feet in relative good weather conditions. While the skydivers attempted to jump, the pilot lost control of the airplane that nosed down and entered a dive. In a vertical position, the airplane spiraled to the ground and lost part of its right wing before crashing in a wooded area located on the Storsandskär Island, about 2 km southeast of Umeå Airport. The aircraft was totally destroyed upon impact and all nine occupants were killed. Five days after the accident, on July 19, EASA published an Emergency Airworthiness Directive indicating that the airplane suffered structural failure and that a wing may have detached from the aeroplane prior to the accident, but, at this time, the root cause of the accident cannot be confirmed. For these reasons, all operations of the GA8 Airvan have been prohibited from July 20 for 15 days.
Based on that history and what little is known about the crash, the Director of Civil Aviation Safety Authority (CASA) issued the following statement:
Director of Civil Aviation Graeme Harris said the grounding was not a decision made lightly.
“I have sufficient concerns about the safety of these aircraft to make it necessary for me to ground them until more is known about the cause of the 14 July crash in Sweden that killed all 9 people on board a GA8 Airvan,” he said in a statement.
“We do not take these steps lightly but when there is a reasonable doubt about the safety of an aircraft, the flying public, operators and pilots of the affected aircraft in New Zealand must be satisfied that the CAA will act with their safety as a priority.”
“Whilst I regret any inconvenience this grounding will cause and acknowledge its significant commercial impact, I simply cannot compromise when I have information that indicates any unacceptable risk.”
EASA’s Emergency AD read as follows—referencing the action of Australia as the authority which issued the TC:
Emergency Airworthiness Directive
AD No.: 2019-0177-E
Issued: 19 July 2019
CASA Australia, the authority of the State of Design of the affected type design, has informed EASA
that a Direction will be issued, which provides for the temporary prohibition of operations of the
GA8 Airvan in Australia. The Direction will take effect on 20 July 2019 and will be valid for 15 days.
Based on all available information, and taking into account the Australian Direction, EASA has
decided to ground the affected aeroplanes registered in EASA Member States, until further notice.
What do the laws and rules state about AD issuance:
In 2002, the FAR Part defining Airworthiness Directives was revised and the scriveners were instructed to follow the plain English style or rule-writing. The statutory bases for issuing an AD are 49 U.S. Code § § 106, 40113 and 44701; none provide an inkling of what the evidentiary standard should be. So, it is not entirely surprising that the actual rule, §39.5 When does FAA issue airworthiness directives?, is far from precise the level of proof of an unairworthy condition exists:
FAA issues an airworthiness directive addressing a product when we find that:
(a) An unsafe condition exists in the product; and
One way to understand the exact meaning of a regulation is to file a Request for Interpretation from the Chief Counsel, but unfortunately if there is an opinion of the evidentiary standard for §39.5, my search did not find it.
Applying §39.5 to GA8 facts
According to B3A, the three CAAs, which issued Emergency ADs, acted
- with the knowledge that the wing separated,
- but the structural failure may have been the result of the stresses caused by forces of the spin,
- and with a nineteen year history of operations with only 5 accidents.
Thus the first standard, “an unsafe condition exists”, was met. From the single incident, without any further information that the failure was endemic to the GA8 fleet, it seems to be a stretch to assert that the “condition is likely to exist or develop in other products of the same type design.”
Type Certification now accepts risk analyses in approving an aircraft; perhaps an interpretation of §39.5 could include some standard.
It should also be noted the EASA issuance of the emergency AD was preceded by a statement by the State of Design. Another means of refining the standard for issuance of Emergency Airworthiness Directives involving aircraft certificated by one country and operating in another, it might be worthwhile to amend Bilateral Airworthiness Agreements or the higher standard Bilateral Aviation Safety Agreements.
Aeronautical manufacturing is increasingly global and trending towards hyper competition. Under those circumstances, it appears to be auspicious to define with greater precision what a CAA must know in order to issue an Emergency AD.
 Manager-AFS-300 – (2008) Legal Interpretation (PDF); Schultz – (2009) Legal Interpretation (PDF), Griffin-GreenbergTraurig – (2013) Legal Interpretation (PDF); Collins – (2011) Legal Interpretation (PDF) inter alia
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